Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Case of the Locked Hothouse

You may play an additional land on each of your turns.
To solve — You control seven or more lands. (If unsolved, solve at the beginning of your end step.)
Solved — You may look at the top card of your library any time, and you may play lands and cast creature and enchantment spells from the top of your library.

Gruul Guildgate

This land enters tapped.
{T}: Add {R} or {G}.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.

Solemnity

Players can't get counters.
Counters can't be put on artifacts, creatures, enchantments, or lands.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Sage of the Maze

{T}: Add two mana in any combination of colors.
{T}: Until end of turn, target land you control becomes an X/X Citizen creature with haste in addition to its other types, where X is twice the number of Gates you control. Activate only as a sorcery.
Tap an untapped Gate you control: Untap this creature.

Summer Bloom

You may play up to three additional lands this turn.

Ancient Greenwarden

Reach (This creature can block creatures with flying.)
You may play lands from your graveyard.
If a land entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

District Guide

When this creature enters, you may search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Perennial Behemoth

You may play lands from your graveyard.
Unearth {G}{G} ({G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Mutated Cultist

Devoid (This card has no color.)
When you cast this spell, remove all counters from up to one target permanent or opponent. The next spell you cast this turn costs {1} less to cast for each counter removed this way.
Deathtouch

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of this creature instead.

Saskia the Unyielding

Vigilance, haste
As Saskia enters, choose a player.
Whenever a creature you control deals combat damage to a player, it deals that much damage to the chosen player.

Dark Depths

Dark Depths enters with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to that card's mana value.

Mossborn Hydra

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
This creature enters with a +1/+1 counter on it.
Landfall — Whenever a land you control enters, double the number of +1/+1 counters on this creature.

Cliffgate

This land enters tapped.
As this land enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Citadel Gate

This land enters tapped.
As this land enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Marshal's Anthem

Multikicker {1}{W} (You may pay an additional {1}{W} any number of times as you cast this spell.)
Creatures you control get +1/+1.
When this enchantment enters, return up to X target creature cards from your graveyard to the battlefield, where X is the number of times this enchantment was kicked.

Sylvan Scrying

Search your library for a land card, reveal it, put it into your hand, then shuffle.

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

Gladiolus Amicitia

When Gladiolus Amicitia enters, search your library for a land card, put it onto the battlefield tapped, then shuffle.
Landfall — Whenever a land you control enters, another target creature you control gets +2/+2 and gains trample until end of turn.

Elvish Reclaimer

This creature gets +2/+2 as long as there are three or more land cards in your graveyard.
{2}, {T}, Sacrifice a land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Ramunap Excavator

Fear of Missing Out

When this creature enters, discard a card, then draw a card.
Delirium — Whenever this creature attacks for the first time each turn, if there are four or more card types among cards in your graveyard, untap target creature. After this phase, there is an additional combat phase.

Circuitous Route

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.

Crackling Perimeter

Tap an untapped Gate you control: This enchantment deals 1 damage to each opponent.

Gates Ablaze

Gates Ablaze deals X damage to each creature, where X is the number of Gates you control.

Navigation Orb

{2}, {T}, Sacrifice this artifact: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Reap and Sow

Choose one —
• Destroy target land.
• Search your library for a land card, put that card onto the battlefield, then shuffle.
Entwine {1}{G} (Choose both if you pay the entwine cost.)

Orzhov Guildgate

This land enters tapped.
{T}: Add {W} or {B}.

Gatekeeper Gargoyle

Flying
This creature enters with a +1/+1 counter on it for each Gate you control.

Gate Colossus

Affinity for Gates (This spell costs {1} less to cast for each Gate you control.)
This creature can't be blocked by creatures with power 2 or less.
Whenever a Gate you control enters, you may put this card from your graveyard on top of your library.

Black Dragon Gate

This land enters tapped.
As this land enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Vampire Hexmage

First strike
Sacrifice this creature: Remove all counters from target permanent.

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Weathered Wayfarer

{W}, {T}: Search your library for a land card, reveal it, put it into your hand, then shuffle. Activate only if an opponent controls more lands than you.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Festering Wound

Enchant creature
At the beginning of your upkeep, you may put an infection counter on this Aura.
At the beginning of the upkeep of enchanted creature's controller, this Aura deals X damage to that player, where X is the number of infection counters on this Aura.

Hold the Gates

Creatures you control get +0/+1 for each Gate you control and have vigilance.

Maja, Bretagard Protector

Other creatures you control get +1/+1.
Landfall — Whenever a land you control enters, create a 1/1 white Human Warrior creature token.

Exploration Broodship

Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery. It's an artifact creature at 8+.)
3+ | You may play an additional land on each of your turns.
8+ | Flying
Once during each of your turns, you may cast a permanent spell from your graveyard by sacrificing a land in addition to paying its other costs.

Gatecreeper Vine

Defender
When this creature enters, you may search your library for a basic land card or a Gate card, reveal it, put it into your hand, then shuffle.

Aether Snap

Remove all counters from all permanents and exile all tokens.

Manor Gate

This land enters tapped.
As this land enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Exploration

You may play an additional land on each of your turns.

Talon Gates of Madara

When this land enters, up to one target creature phases out.
{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{4}: Put this card from your hand onto the battlefield.

Golgari Guildgate

This land enters tapped.
{T}: Add {B} or {G}.

Maze's End

This land enters tapped.
{T}: Add {C}.
{3}, {T}, Return this land to its owner's hand: Search your library for a Gate card, put it onto the battlefield, then shuffle. If you control ten or more Gates with different names, you win the game.

Gateway Plaza

This land enters tapped.
When this land enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Full Throttle

After this main phase, there are two additional combat phases.
At the beginning of each combat this turn, untap all creatures that attacked this turn.

Braulios of Pheres Band

Braulios's power and toughness are each equal to the number of lands you control.
Whenever Braulios attacks, draw a card, then you may put a land card from your hand onto the battlefield.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Wight of the Reliquary

Vigilance
This creature gets +1/+1 for each creature card in your graveyard.
{T}, Sacrifice another creature: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Tempt with Discovery

Tempting offer — Search your library for a land card and put it onto the battlefield. Each opponent may search their library for a land card and put it onto the battlefield. For each opponent who searches a library this way, search your library for a land card and put it onto the battlefield. Then each player who searched a library this way shuffles.

Ouroboroid

At the beginning of combat on your turn, put X +1/+1 counters on each creature you control, where X is this creature's power.

Gatebreaker Ram

This creature gets +1/+1 for each Gate you control.
As long as you control two or more Gates, this creature has vigilance and trample.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Ulvenwald Hydra

Reach
Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.
When this creature enters, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

The Black Gate

As The Black Gate enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.
{1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.

Nahiri's Lithoforming

Sacrifice X lands. For each land sacrificed this way, draw a card. You may play X additional lands this turn. Lands you control enter tapped this turn.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)